Mendelian Genetics (1)

• Who is known as the father of genetics?

  Gregor Johann Mendel
• What are the major postulates of transmission genetics?


  They describe how discrete units of inheritance behave during gamete formation.
• What plant did Mendel use for his experiments?

  Garden pea (Pisum sativum)
• What did Mendel predict about discrete units of inheritance?


  They exist and predict their behavior during gamete formation.
• What is transmission genetics?


  It is the study of how genes are transmitted from parents to offspring.
• When did Mendel conduct his first experiment using garden peas?


  1856
• What did Mendel demonstrate through his methodology in experimental biology?


  He showed remarkable insight into the methodology necessary for good experimental biology.
• Why are garden peas considered a good model organism for genetic studies?


  They are easy to grow, hybridize artificially, self-fertilizing, and mature in one season.
• How many visible features did Mendel study in garden peas?


  Seven visible features
• What does true breeding mean in Mendel's experiments?

  It means the character remains unchanged generation after generation in fertilizing plants.
• What is a monohybrid cross?

  It involves only one pair of contrasting traits from two parent strains.
• What are the generations involved in Mendel's crosses?


  P1 is the parental generation, F1 is the first filial generation, and F2 is the second filial generation.
• What was the result when Mendel crossed tall plants with dwarf plants in the F1 generation?


  The resulting F1 generation consisted only of tall plants.
• What did Mendel observe in the F2 generation after selfing the F1 generation?


  There were 787 tall plants and 277 dwarf plants, indicating the dwarf trait reappeared.
• What did Mendel propose to explain the results of his experiments?


  He proposed the existence of particular unit factors for each trait.
• What are unit factors in pairs also known as?


  They are known as the principle of paired factors.
• How do unit factors exist in diploid individuals?


  Each diploid individual receives one factor from each parent.
• What combinations of factors are possible in Mendel's experiments?


  Two factors for tall (TT), two factors for dwarf (tt), or one factor for each trait (Tt).
• What is the phenotype?

  It is the visible and observable traits of an individual.
• What is the genotype?

  It is the genetic constitution of an individual.
• What happens when two unlike unit factors are present in an individual?


  One unit factor is dominant, and the other is recessive.
• How is the dominant trait expressed in the F1 generation?


  It is controlled by the dominant unit factor.
• How are dominant and recessive unit factors represented?


  Dominant is uppercase and italicized, while recessive is lowercase and italicized.
• What occurs during the formation of gametes according to Mendel's segregation principle?


  The paired unit factors separate randomly so that each gamete receives one or the other.
• What do Mendel's unit factors represent in modern genetics?


  They represent units of inheritance called genes.
• What determines the phenotype of an individual?


  The phenotype is determined by alternative forms of a single gene called alleles.
• What are alleles when written in pairs?


  They represent the two unit factors (DD, Dd, or dd) and are called the genotype.
• What does it mean if an individual is homozygous?


  It means having two identical alleles (PP or pp).
• What does it mean if an individual is heterozygous?


  It means having two different alleles (Pp).
• Who is the testcross named after?

  Reginald C. Punnett
• What does the vertical column and horizontal row represent in a Punnett square?


  The vertical column represents the female parent, and the horizontal row represents the male parent.
• What does a Punnett square list?


  It lists all possible random fertilization events and the genotypes and phenotypes of potential offspring.
• What is the dominant phenotype?


  It is the phenotype seen when two alternative alleles are present together (Pp: purple).
• What is the dominant allele?


  It is the form of the gene that is expressed when two alternative alleles are present together (P>P).
• What is the recessive allele?


  It is the form of the gene that is not expressed when two alternative alleles are present together.
• What is the recessive phenotype?


  It is the phenotype that is only seen when two identical alleles are found together (pp: white).
• What does homozygous mean?


  It means having two identical alleles (PP or pp).
• What does heterozygous mean?


  It means having two different alleles (Pp).